Yet in New Zealand where almost every native tree is evergreen, the emphasis on trees changing colour and losing they leaves could seem to favour introduced trees over native trees. Here are some activities and ideas for studying native tree leaves in New Zealand. Autumn is still a good time to study leaves as it is interesting to compare deciduous and evergreen trees.
ACTIVITY: Go on a leaf hunt to find different colour leaves and identify whether trees are evergreen or deciduous.
Deciduous trees - those that lose their leaves in autumn - do so to survive a cold winter, saving energy and getting rid of leaves that might pick up diseases. The trees draw back into their branches and trunk all the goodness that was in the leaves, such as water, nutrients and the green substance chlorophyll. So the leaves change colour, dry out and fall.
There are some parts of New Zealand where many deciduous introduced trees have been planted. Even in a warmer climate they continue to loose their leaves in autumn.
Autumn leaves of deciduous trees in Nelson, New Zealand |
Pōhutukawa leaf collection - despite the range of colours found, pōhutkawa is not a deciduous tree, always look up into the tree itself to see whether the leaves are all changing colour |
Dead leaves form leaf litter on the forest floor. Eventually these leaves rot and breakdown along with other plant matter to form soil. The last part to rot is often the vein structure.
Leaf litter under mahoe and kohekohe trees |
The fine detail of a skeleton leaf |
ACTIVITY: Making Leaf Art - clay impressions, leaf rubbings, leaf prints
If you look closely you'll see how different trees have quite different arrangements of veins in their leaves. Veins carry food and water back and forth. The green substance in leaves - chlorophyll - turns the sun's energy into food. The tree also gets nutrients and water from the ground some of which would go to the leaves.
Some leaves have very clear veins, sunshine through a pukanui leaf highlights the vein structure |
Leaf impressions in clay used to create pottery bowls and plates |
Leaf rubbings in a nature journal, the pencil colours match the colour of the leaves |
Rangiora leaf print |
Kawakawa leaf print |
ACTIVITY: Go on a leaf scavenger hunt to find leaves of different shapes and textures
Did you know?
Did you know tough leaves of mutton bird scrub were used to write letters or postcards and mailed from Ulva Island in Rakiura/ Stewart Island? The ferry to Ulva Island still uses these leaves as tickets today. The underside of the leaf is soft and white, making a perfect writing surface.
Reusable ferry tickets (and compostable when they get too worn out) |
Rangiora leaves have many uses but they are poisonous |
Trees and shrubs that live by the sea, such as mutton bird scrub and pohutukawa, often have tough or shiny leaves to enable them to survive the salt spray and strong winds. Another common example is taupata.
Taupata can survive salt winds |
Some trees have leaves that are made up of several leaf blades grouped together, the general name for this is compound leaves. When they look a bit like fingers, the name for this is palmate. An example, is five finger, here all five leaf blades count as one leaf.
Five finger or whauwhaupaku |
Another tree with compound leaves, is kowhai, in this case the leaf blades are grouped lengthwise and are called pinnate
Kowhai |
Some trees have leaves that are not all the same shape, young horoeka /lancewood trees have one shape leaf and as they get older the leaves change. Occasionally you can see both types of leaf on the same tree.
Kotukutuku, native tree fuchsia is one of the few native trees that is deciduous.
Kotukutuku, native tree fuchsia is one of the few native trees that is deciduous.
Trampers walk through bare kotuktuku trees in the spring |
Kotukutuku flowers and leaves |
More information about trees and native plants:
On Science Learn for schools
On Science Learn for schools
https://www.sciencelearn.org.nz/resources/2634-identifying-native-plants
On NZ Plant Conservation Network clear training module on plant ID
https://www.nzpcn.org.nz/conservation/training/module-1-plant-life/
iNaturalist for identification of your observations
On NZ Plant Conservation Network clear training module on plant ID
https://www.nzpcn.org.nz/conservation/training/module-1-plant-life/
iNaturalist for identification of your observations
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